This research proposal is designed to test whether sodium phenylbutyrate (SPB) will increase fetal hemoglobin (HbF) in children with sickle cell anemia & thereby ameliorate complications from their disease. Red blood cell sickling occurs in patients with sickle cell anmia because deoxygenated hemoglobin S(HbS) aggregates into rigid, rod-like polymers. The normal bi-concave red blood cell disc assumes a sickle shape, which is much less deformable & tends to fragment in the circulation. Moreover, abnormal membraane properties cause adherence to the vascular endothelium. The combination of these physical abnormalities give rise to the anemia & vaso-occlusivephenomenon associated with the disease.